The present invention relates to an apparatus for controlling an operation of a shutter, and more specifically, relates to an apparatus for controlling an opening operation of shutter sectors, provided in a camera with a lens shutter.
Conventionally, a shutter operation control apparatus is provided for controlling the opening/closing a lens shutter of a camera. The control apparatus is provided with a shutter control plate which controls the opening/closing shutter sectors or the exposure by moving it reciprocally. More specifically, the shutter control plate has a sector cam surface with which a pin of a sector lever coupled to the shutter sector is engaged. When the shutter control plate moves reciprocally, the sector ever swings according to the profile of the sector cam surface, thereby opening/closing the shutter sectors.
It should be noted that since the sector cam surface is formed on the shutter control plate only in a part and the profile of the sector cam surface is constituted by an inclined flat surface, the movement of the shutter control plate while the sector cam surface and the pin of the sector lever is engaged with each other is set to be a substantially constant-speed linear movement. Accordingly, the size of the aperture of the shutter suddenly becomes large at the commencement of the opening of the shutter; in other words, when the size of the aperture is set to be relatively small.
Consequently, in photographing under a high luminance where the size of the aperture is set to be small, an F-number will greatly change even though the opening rate of the aperture of the shutter sectors or the shutter speed is slightly increased or decreased. As a result, problems will arise where the dispersion of the exposure has happened, and the accuracy of the exposure has been lowered.